Modeling Soft Material Adhesion for In vivo Robotic Locomotion

In a continued effort to develop an active Robotic Capsule Endoscope (RCE), research is being conducted on the motion of the RCE through the small and large bowel. One of the factors in uencing the motion of the RCE is the adhesion of the RCE's micropatterned treated wheels to the inner lumen of bowel tissue. While adhesion is needed to generate traction, too much adhesion can also cause malfunctioning of the device, reduce autonomy and damage the tissue. This study is focused on the characterization of adhesion as a function of three critical RCE design parameters (Pre-load, Dwell Time and Separation Rate). In this work, a method for adhesion characterization is detailed and a complete model for the adhesion between a cylindrical probe with a smooth polydimethlysiloxane (PDMS) surface and synthetic tissue is presented. An explicit nondimensional model for the adhesive response is constructed with an R2 value of 0.9996 and a maximum relative error less than 5.6%. In addition, physical meaning of the proposed mathematical model is experimentally verified. Accurate models for the maximum stress supported by the tissue (R2 = 0:9895, maximum error = 2:04%), effective adhesion energy consumed in the separation (R2 = 0:9936, maximum error = 3:23%) and the total probe displacement from the beginning of the adhesion region to the point where complete separation occurs (R2 = 0:9964, maximum error = 1:47%) as a function of critical design parameters are obtained. Finally, a qualitative approach to the extrapolation of these models when varying the substrate stiffness and probe area is presented.Outgoin

Spherical Wrist Manipulator Local Planner for Redundant Tasks in Collaborative Environments

: Standard industrial robotic manipulators use well-established high performing technologies. However, such manipulators do not guarantee a safe Human-Robot Interaction (HRI), limiting their usage in industrial and medical applications. This paper proposes a novel local path planner for spherical wrist manipulators to control the execution of tasks where the manipulator number of joints is redundant. Such redundancy is used to optimize robot motion and dexterity. We present an intuitive parametrization of the end-effector (EE) angular motion, which decouples the rotation of the third joint of the wrist from the rest of the angular motions. Manipulator EE motion is controlled through a decentralized linear system with closed-loop architecture. The local planner integrates a novel collision avoidance strategy based on a potential repulsive vector applied to the EE. Contrary to classic potential field approaches, the collision avoidance algorithm considers the entire manipulator surface, enhancing human safety. The local path planner is simulated in three generic scenarios: (i) following a periodic reference, (ii) a random sequence of step signal references, and (iii) avoiding instantly introduced obstacles. Time and frequency domain analysis demonstrated that the developed planner, aside from better parametrizing redundant tasks, is capable of successfully executing the simulated paths (max error = 0.25°) and avoiding obstacles

Draft genome sequences of Mycobacterium setense type strain DSM-45070 and the nonpathogenic strain Manresensis, isolated from the bank of the Cardener River in Manresa, Catalonia, Spain

We present here the draft genome sequences of two Mycobacterium setense strains. One of them corresponds to the M. setense type strain DSM-45070, originally isolated from a patient with a posttraumatic chronic skin abscess. The other one corresponds to the nonpathogenic M. setense strain Manresensis, isolated from the Cardener River crossing Manresa, Catalonia, Spain. A comparative genomic analysis shows a smaller genome size and fewer genes in M. setense strain Manresensis relative to those of the type strain, and it shows the genome segments unique to each strain

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Modeling Soft Material Adhesion for In vivo Robotic Locomotion

In a continued effort to develop an active Robotic Capsule Endoscope (RCE), research is being conducted on the motion of the RCE through the small and large bowel. One of the factors in uencing the motion of the RCE is the adhesion of the RCE's micropatterned treated wheels to the inner lumen of bowel tissue. While adhesion is needed to generate traction, too much adhesion can also cause malfunctioning of the device, reduce autonomy and damage the tissue. This study is focused on the characterization of adhesion as a function of three critical RCE design parameters (Pre-load, Dwell Time and Separation Rate). In this work, a method for adhesion characterization is detailed and a complete model for the adhesion between a cylindrical probe with a smooth polydimethlysiloxane (PDMS) surface and synthetic tissue is presented. An explicit nondimensional model for the adhesive response is constructed with an R2 value of 0.9996 and a maximum relative error less than 5.6%. In addition, physical meaning of the proposed mathematical model is experimentally verified. Accurate models for the maximum stress supported by the tissue (R2 = 0:9895, maximum error = 2:04%), effective adhesion energy consumed in the separation (R2 = 0:9936, maximum error = 3:23%) and the total probe displacement from the beginning of the adhesion region to the point where complete separation occurs (R2 = 0:9964, maximum error = 1:47%) as a function of critical design parameters are obtained. Finally, a qualitative approach to the extrapolation of these models when varying the substrate stiffness and probe area is presented.Outgoin

Modeling Soft Material Adhesion for In vivo Robotic Locomotion

In a continued effort to develop an active Robotic Capsule Endoscope (RCE), research is being conducted on the motion of the RCE through the small and large bowel. One of the factors in uencing the motion of the RCE is the adhesion of the RCE's micropatterned treated wheels to the inner lumen of bowel tissue. While adhesion is needed to generate traction, too much adhesion can also cause malfunctioning of the device, reduce autonomy and damage the tissue. This study is focused on the characterization of adhesion as a function of three critical RCE design parameters (Pre-load, Dwell Time and Separation Rate). In this work, a method for adhesion characterization is detailed and a complete model for the adhesion between a cylindrical probe with a smooth polydimethlysiloxane (PDMS) surface and synthetic tissue is presented. An explicit nondimensional model for the adhesive response is constructed with an R2 value of 0.9996 and a maximum relative error less than 5.6%. In addition, physical meaning of the proposed mathematical model is experimentally verified. Accurate models for the maximum stress supported by the tissue (R2 = 0:9895, maximum error = 2:04%), effective adhesion energy consumed in the separation (R2 = 0:9936, maximum error = 3:23%) and the total probe displacement from the beginning of the adhesion region to the point where complete separation occurs (R2 = 0:9964, maximum error = 1:47%) as a function of critical design parameters are obtained. Finally, a qualitative approach to the extrapolation of these models when varying the substrate stiffness and probe area is presented.Outgoin

Spherical Wrist Manipulator Local Planner for Redundant Tasks in Collaborative Environments

Standard industrial robotic manipulators use well-established high performing technologies. However, such manipulators do not guarantee a safe Human–Robot Interaction (HRI), limiting their usage in industrial and medical applications. This paper proposes a novel local path planner for spherical wrist manipulators to control the execution of tasks where the manipulator number of joints is redundant. Such redundancy is used to optimize robot motion and dexterity. We present an intuitive parametrization of the end-effector (EE) angular motion, which decouples the rotation of the third joint of the wrist from the rest of the angular motions. Manipulator EE motion is controlled through a decentralized linear system with closed-loop architecture. The local planner integrates a novel collision avoidance strategy based on a potential repulsive vector applied to the EE. Contrary to classic potential field approaches, the collision avoidance algorithm considers the entire manipulator surface, enhancing human safety. The local path planner is simulated in three generic scenarios: (i) following a periodic reference, (ii) a random sequence of step signal references, and (iii) avoiding instantly introduced obstacles. Time and frequency domain analysis demonstrated that the developed planner, aside from better parametrizing redundant tasks, is capable of successfully executing the simulated paths (max error = 0.25°) and avoiding obstacles